Abstract
The influence that oxygen has on the burning behaviour of cotton single- and multilayered fabries has been determined by recording persistence of burning times as a function of oxygen concentration. For a given fabric subjected to a specified igniter application time, an extinction oxygen index parameter, EOI, may be determined. EOI is defined as the oxygen concentration expressed as a volume fraction in an oxygen-nitrogen mixture, necessary to give a persistence of burning time equal to zero. For a given fabric, EOI is found to decrease as the igniter application time increases and two limiting EOI values may be observed, one corresponding to zero inginter application conditions and one for igniter application times greater than 10 s. At any given ignition time, the extinction oxygen index increases linearly with fabric area density and decreases linearly with the logarithm of the respective air permeability. Similar results are observed for nylon 6.6 and polyester single- and multilayered fabrics. The validity of the extinction oxygen index is discussed with reference to other published works.